In prior art, antenna signals are fed in either a series-fed manner or a parallel-fed manner. A series-fed antenna architecture is schematically illustrated in FIG. 1A. As shown, a series of antenna units 100A are coupled to each other with respective input ends interconnected so as to form a one-dimensional antenna array A1, and the one-dimensional antenna array A1 has a common feeding point P1. Likewise, other one-dimensional antenna arrays A2, A3 and A4 are formed with respective feeding points P2, P3 and P4. The four longitudinal antenna arrays A1, A2, A3 and A4 are further combined into a two-dimensional antenna array AA1 with specific phase differences and intensity weight ratios of input signals, which are fed into the antenna array AA1 from the four feeding points P1, P2, P3 and P4. On the other hand, a parallel-fed antenna architecture is schematically illustrated in FIG. 1B. As shown, an input signal is fed into the two-dimensional antenna array AA2 through a feeding point P5. The two-dimensional antenna array AA2 is formed with four one-dimensional antenna arrays A5, A6, A7 and A8, and each of the antenna arrays A5, A6, A7 and A8 includes a plurality of antenna units 100B connected in parallel. In the two-dimensional antenna array AA2, phase differences and signal-intensity weight ratios associated with the four longitudinal antenna arrays A5, A6, A7 and A8 are controlled by way of impedance matching among transmission lines, and meanwhile, phase differences and signal-intensity weight ratios of the antenna units 100B in each of the antenna arrays A5, A6, A7 and A8 are also controlled by way of impedance matching among transmission lines.
No matter which kind of antenna architecture is adopted for designs, signal transmission lines are required to directly couple the feeding points to the one-dimensional antenna arrays. This confines the freedom of wiring designs of the entire antenna array. Moreover, the resulting traces would occupy a significant area of the antenna array and cause undesired interference. Miniaturization of the antenna array is hard to be achieved.